I know this might sound weird but I'm just thinking that.....would it be possible to install two different anti-virus in same computer?

Yes, you can use 2 AV programs on the same computer. You should exclude each AV's program and data folders from the other and the signature and quarantine folders if they are not in the data folder (ClamWin has its signature and quarantine folders in its data folder).

I use Clam Sentinel/ClamWin, Microsoft Security Essentials, and Malwarebytes Pro on my Windows 7 computer and they work together pretty well with the above exclusions. My CPU use during manual scans is usually no more than 50%, with an occasional spike when all AVs trigger on the same file. I have used this combination for a couple of years now. I generally recommend no more than 2 AVs on one computer, but I use 3 AVs because I work with malware. I also recommend that you use one AV program and one antimalware (or antispyware) program because each one will scan a bit differently, so they do not exactly duplicate each other.

Microsoft Security Essentials lets you exclude processes, so you do not have to exclude the other AV's program folder from it--just exclude every .exe file in the other AV's program folder along with the data folder (including quarantine and signatures). Avira AntiVir lets you exclude processes also. I think this works a little better than excluding the program folder.

Regards,