Hi Zak,
I’m assuming you have a wireless keyboard which won’t work during the boot scan because the drivers aren’t loaded.
You can either change the bios settings so that the keyboard works during the scan, or change the scan settings so that malware found is sent to the chest (quarantine) without requiring any key press from you.
You can find more info on the bios option by doing a forum search.
Here are some more scanning options to try as well:
Look for and remove rootkits (hidden malware):
Panda Antirootkit
Blacklight
AVG Anti-Rootkit
Try a scan with DrWeb CureIT!
Try the usual free adware/spyware scanners.
AVG Anti-Spyware Free (Requires Win2k/XP)
Ad-Aware Free
Spybot Search & Destroy
SUPERAntiSpyware Free
a-Squared Free
Download, install and update all the programs. Disconnect from the internet (pull the plug) before running scans in Safe Mode if possible.
Always select the option to quarantine any malware found rather than delete it, then you will be able to restore files or registry entries wrongly identified as malware- a rare but not unknown event for any malware scanner.
Try some online scans. (Disable avast! while scanning.)
F-Secure
BitDefender
Panda
Trend Micro Housecall
If still having problems, post a HijackThis! log.
When you have finished, scan for out-of-date and insecure software using Secunia Software Inspector and update any vulnerable software: this will help to prevent future infections.