I use
PcPitstop website it has an online virus checker (antivirus center)
Test Your Internet Connection
Check Your PC for Viruses
Test Your ActiveX Support
you can run Full tests online on your pc
Disk Fragmentation Analysis
System Resource Analysis
Device Driver Analysis
CPU Benchmark Test
Video Benchmark Test
Memory Benchmark Test
Detailed System Inventory
Spyware Check
In-Memory Virus Check
Internet Download Performance
Internet Upload Performance
Internet Ping Test
Internet Security Test
and more
its worth a visit if you havent already done so