hi all

[tavi]

hi,i just downloaded a free version of avast pro...and i scanned my laptop....seems i had a virus,trojan....and every error gives i make..repair...program cannot repair..and..i make delete all...   and some of files have been from windows.....i'm not a programmer,but i tell you what i saw..the exe files from windows,some of them are missing....and now,appears nothing on my desktop......it's logged on but only when i press ''ctrl lt del'' i can see the process on the screen,and give  a new task.i tried system restore but nothing changed....if anyone know how i can fix that,because reinstalling windows..(i lost the original cd)...and my laptop i've used with an external dvd rom,wich i have no more....thanks a lot

[DavidR]

What is the infected file name, where was it found e.g. (C:\windows\system32\infected-file-name.xxx) ? 
Check the avast! Log Viewer (right click the avast 'a' icon), Warning section, this contains information on all avast detections.

It is not uncommon for malware to try to place files in the system folders to disuade people from getting rid of them.

Deletion isn't really a good first option (you have none left), 'first do no harm' don't delete, send virus to the chest and investigate.