This time a problem for me

This time the problem is serious
I see a lot of viruses running in my task manager
viz. yybsa.exe,swope.exe,winosar.exe and all funny names you can think of.
these all reside in 'local settings\temp'
my picture viewer,wordpad and logonui have been deleted

I had AVG, I uninstalled it a day, later when I tried to install it, it always showed some problem and didn't install,
I tried Kasper, it refused as it said there was AVG still in my PC,
I then tried Avast, most of my setups got corrupted after download, but I retained a file.

As soon as the installation starts, the pc reboots,
I tried safe mode,
a msg appears after the loading of all files-
press escape to cancel loading STDP.sys
If I press Esc, it reboots, If I don't, the too it reboots

I tried directory restore mode, it ran the safe mode,
I tried installing Avast, it rebooted.

I finally deleted all reg keys referencing AVG, Kasper then got installed, but it is unfunctional, it doesn't even run. The option in context menu also remains fade.

I downloaded a logonui and tried it in its place, but it too doesn't works

I get a lot of error msgs before logon with tu_logonui as title and some msg

Also I'm unable to hibernate, sometimes my mouse stops working and the device manager shows no such device