恢复内核版本更改

Question

我正在尝试安装virtualbox-dkms，并尝试通常的sudo apt-get- install virtualbox-dkms结果：

Preparing to unpack .../virtualbox-dkms_4.3.10-dfsg-1ubuntu5_all.deb ...
Unpacking virtualbox-dkms (4.3.10-dfsg-1ubuntu5) ...
Setting up virtualbox-dkms (4.3.10-dfsg-1ubuntu5) ...
Loading new virtualbox-4.3.10 DKMS files...
First Installation: checking all kernels...
Building only for 3.17.0-focaltech-debug
Building initial module for 3.17.0-focaltech-debug
ERROR (dkms apport): kernel package linux-headers-3.17.0-focaltech-debug is not supported
Error! Bad return status for module build on kernel: 3.17.0-focaltech-debug (x86_64)
Consult /var/lib/dkms/virtualbox/4.3.10/build/make.log for more information.
 * Stopping VirtualBox kernel modules                                    [ OK ] 
 * Starting VirtualBox kernel modules
 * No suitable module for running kernel found

invoke-rc.d: initscript virtualbox, action "restart" failed.

读了一遍之后，我发现这似乎是我的内核版本的问题。我该如何将内核更改为3.17.0-focaltech-debug与 VirtualBox 兼容的版本？

编辑：我已将内核版本更改为 3.19.0-31-generic，以下是更新的输出：

不同命令的输出：

apt-cache 策略 virtualbox-dkms

virtualbox-dkms:
  Installed: 4.3.10-dfsg-1ubuntu5
  Candidate: 4.3.10-dfsg-1ubuntu5
  Version table:
 *** 4.3.10-dfsg-1ubuntu5 0
        500 http://ar.archive.ubuntu.com/ubuntu/ trusty-updates/multiverse amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/multiverse amd64 Packages
        100 /var/lib/dpkg/status
     4.3.10-dfsg-1 0
        500 http://ar.archive.ubuntu.com/ubuntu/ trusty/multiverse amd64 Packages

lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.3 LTS
Release:    14.04
Codename:   trusty

uname -a

Linux lydia 3.19.0-31-generic #36~14.04.1-Ubuntu SMP Thu Oct 8 10:21:08 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

dpkg-l'福泰克‘

dpkg-query: no packages found matching *focaltech*