Help! I believe that my computer may have a virus, it began acting up with a message about low Disc space and having to remove unnecessary files or programs to make room to update the virus data base. I deleted what files i could and I’m still getting the low disc space message (delete unnecessary files to make room, some thing along those lines) It has also gotten very sluggish and sounds like it gets louder So i scanned the computer for viruses and it was unable to scan 22 different files, I’m really not to sure what that means can anyone help me? Thanks. Forgot to mention i have the Avast 4.8 home edition if that makes a difference.
Welcome to the forums, jayjaye. 
From what you posted above, I would think that it has nothing to do with a virus (or other malware) but with the fact that your hard drive may be getting full. So, what is the size of your hard disk and how much data is on it?
By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.
Files that can’t be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.
Also, how much free disk space do you have? How much RAM (memory) do you have?
Open MyComputer (Hit the Windows key and the E key to open it)
Then right click on Drive C and select Properties
(Click on picture to enlarge.)