我读过类似的帖子，但找不到适用的答案，所以这是我的情况。 Xubuntu 有时可以正常启动，但有时会陷入循环。以下是我观察到的情况：
默认启动后grub：XUbuntu 蓝屏，带有旋转的弧段，可能会出现，也可能不会出现，但如果出现，并且弧段持续旋转，则启动总是会陷入循环。循环显示fsck结果，然后消失，硬盘活动，可能是屏幕活动，然后fsck再次显示结果。典型的循环时间大约为一分钟或更长时间。
我尝试了几种补救措施（拔掉电脑、显示器的插头等），但似乎都不起作用。启动循环似乎完全是随机的。我在 dmsg 或某些日志中找不到线索。
恢复启动始终正常，并且仅启动到 VGA 图形。
我有 nvidia 显卡，它使用 nouveau 驱动程序。
有什么建议么？
编辑2017年4月25日：在循环中 Ctr=Alt+Fn1 和命令sudo /etc/init.d/lightdm stop并sudo journalctl -xe给我，摘录：
Apr 25 11:02:12 andrasubuntu NetworkManager[1263]: <info> [1493132532.7582] device (enp0s4): Activation: successful, device activated.
Apr 25 11:02:12 andrasubuntu whoopsie[704]: [11:02:12] The default IPv4 route is: /org/freedesktop/NetworkManager/ActiveConnection/0
Apr 25 11:02:12 andrasubuntu whoopsie[704]: [11:02:12] Not a paid data plan: /org/freedesktop/NetworkManager/ActiveConnection/0
Apr 25 11:02:12 andrasubuntu whoopsie[704]: [11:02:12] Found usable connection: /org/freedesktop/NetworkManager/ActiveConnection/0
Apr 25 11:02:12 andrasubuntu whoopsie[704]: [11:02:12] online
Apr 25 11:02:13 andrasubuntu sudo[1513]: janos : TTY=tty1 ; PWD=/home/janos ; USER=root ; COMMAND=/etc/init.d/lightdm start
Apr 25 11:02:13 andrasubuntu sudo[1513]: pam_unix(sudo:session): session opened for user root by janos(uid=0)
Apr 25 11:02:13 andrasubuntu systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit lightdm.service has begun starting up.
Apr 25 11:02:13 andrasubuntu dbus[707]: [system] Activating systemd to hand-off: service name='org.freedesktop.login1' unit='dbus-org.freedesktop.login1.service'
Apr 25 11:02:25 andrasubuntu dbus[707]: [system] Failed to activate service 'org.freedesktop.systemd1': timed out
Apr 25 11:02:25 andrasubuntu systemd-logind[1462]: Failed to enable subscription: Failed to activate service 'org.freedesktop.systemd1': timed out
Apr 25 11:02:25 andrasubuntu systemd-logind[1462]: Failed to fully start up daemon: Connection timed out
Apr 25 11:02:25 andrasubuntu systemd[1]: systemd-logind.service: Main process exited, code=exited, status=1/FAILURE
Apr 25 11:02:25 andrasubuntu systemd[1]: Failed to start Login Service.
-- Subject: Unit systemd-logind.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-logind.service has failed.
--
-- The result is failed.
Apr 25 11:02:25 andrasubuntu systemd[1]: systemd-logind.service: Unit entered failed state.
Apr 25 11:02:25 andrasubuntu systemd[1]: systemd-logind.service: Failed with result 'exit-code'.
Apr 25 11:02:25 andrasubuntu systemd[1]: systemd-logind.service: Service has no hold-off time, scheduling restart.
Apr 25 11:02:25 andrasubuntu systemd[1]: Stopped Login Service.
-- Subject: Unit systemd-logind.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-logind.service has finished shutting down.
Apr 25 11:02:25 andrasubuntu systemd[1]: Starting Login Service...
-- Subject: Unit systemd-logind.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-logind.service has begun starting up.
Apr 25 11:02:37 andrasubuntu dbus[707]: [system] Failed to activate service 'org.freedesktop.PolicyKit1': timed out
Apr 25 11:02:37 andrasubuntu NetworkManager[1263]: <error> [1493132557.5202] auth: could not get polkit proxy: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.PolicyKit1': timed out
Apr 25 11:02:37 andrasubuntu dbus[707]: [system] Failed to activate service 'fi.w1.wpa_supplicant1': timed out
Apr 25 11:02:37 andrasubuntu NetworkManager[1263]: <warn> [1493132557.5296] supplicant: failed to acquire wpa_supplicant proxy: Wi-Fi and 802.1x will not be available (Error calling StartServiceByName for fi.w1.wpa_supplicant1: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'fi.w1.wpa_supplicant1': timed out)
Apr 25 11:02:38 andrasubuntu dbus[707]: [system] Failed to activate service 'org.freedesktop.login1': timed out
Apr 25 11:02:38 andrasubuntu lightdm[1531]: ** (lightdm:1531): WARNING **: Failed to get list of logind seats: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.login1': timed out
Apr 25 11:02:38 andrasubuntu dbus[707]: [system] Activating systemd to hand-off: service name='org.freedesktop.Accounts' unit='accounts-daemon.service'
Apr 25 11:02:50 andrasubuntu dbus[707]: [system] Failed to activate service 'org.freedesktop.systemd1': timed out
Apr 25 11:02:50 andrasubuntu systemd-logind[1537]: Failed to enable subscription: Failed to activate service 'org.freedesktop.systemd1': timed out
Apr 25 11:02:50 andrasubuntu systemd-logind[1537]: Failed to fully start up daemon: Connection timed out
Apr 25 11:02:50 andrasubuntu systemd[1]: systemd-logind.service: Main process exited, code=exited, status=1/FAILURE
Apr 25 11:02:50 andrasubuntu systemd[1]: Failed to start Login Service.
-- Subject: Unit systemd-logind.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit systemd-logind.service has failed.
--
-- The result is failed.
循环清晰可见。对我来说，问题显然与 nvidia 显卡无关。希望这能有所帮助。
答案1
确实没有 A 插槽处理器支持 SSE2。但是我不认为这是问题所在。10 年来，几乎可以肯定您的主板上装有液体填充电容器。众所周知，这些电容器会发生故障，导致许多看似无法解释的故障。有时此电容器故障是确实可见。事实上，多年来，我更换过几块出现类似症状的主板，检查发现电容器膨胀，有些电容器顶部出现裂缝，并且可以看到电解液（棕色粘稠物）泄漏。如果您检查主板并发现这种情况，那么您几乎没有选择。
最简单、最好的选择就是更换一台新电脑。CPU、RAM、存储设备和接口技术比系统设计时有了很大的进步，这些改进有很多好处。
如果预算中没有购买新机器的费用，那么可以在网上、在当地维修店，甚至从你认识的某个人那里以优惠的价格找到二手或翻新的系统，而这个人拥有最先进的技术，纯粹出于性能原因而淘汰旧系统。
最后也是最不具有吸引力的选项（如果你有出色的电烙铁使用技巧）是将主板上的电容器更换为具有相同特性和规格。电容器非常便宜，但工作本身却非常痛苦且充满风险。