Blank Screen On Logon computer - Don't want to reinstall

I get a Black Screen with only the mouse pointer ! Ctrl + Alt + Del or anything else for that matter doesnt work . Tried logging on into safe mode same result even the command prompt option does the same .
I had been infected with a couple of viruses prior to this I used Kaspersky & Malware Bytes(Both trial Versions) It was a success
But suddenly after 2 days this happened .
First wasnt able to even see the windows logo on XP or get into the safe mode or the command prompt(BTW I have Dual boot with Windows 7 same problem I removed it now) but was able to change a few entries in HKLM/System which enabled me to logon But unable to proceed further.
I doubt that the anti-viruses have deleted some dll and sys files in %windir% and system32 folder as it was patched with the virus . The virus was active even in the safe mode it kept changing the admin password as well I used a few workarounds to remove them I dont like all my effort go in vain lol Its been more than a month now Ive tried everything but reinstall. I know Im overlooking something basic and simple . ;)
I have backed my data using Ubuntu but do not have an install disc . So please Advice. :o