Failed to detect HDD / cannot boot up PC - please help

I think my PC was initially infected by a malware/virus/trojan. I visited a website using Google chrome and then I received a warning of a virus, so I immediately closed the browser. Prior to that, I also downloaded Open Canvass, a free trial software for graphic manipulation. I used MS Security Essential before I installed the software and nothing bad was detected.

However, after I closed the browser and I restarted my PC, unusual thing happened, and a blue screen with so many writings (I didn't have a chance to read) appeared and my system was stopped. When I rebooted the system, Bios couldn't detect my HDD. I use Sata 2 HDD, and it's been working perfectly well in the past few years. Ever since then, my PC couldn't detect HDD and I must keep trying to manually working on Bios or changing Bios in order for the PC to detect HDD and start Windows.

I was thinking to remove virus/trojan/malware, and I used MS Defender Offline on separate CD. But, nothing was detected. So, I reinstalled my Vista 32 bits, and I removed Windows.old and also 2 others odd folders with long names (one of which had numerical numbers 750 etc etc).

Just recently, I became aware of Event Viewer and I noticed errors whenever PC rebooted or Windows started.

Catalog Database (1436) Catalog Database: The database page read from the file "C:\Windows\system32\CatRoot2\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\catdb" at offset 1187840 (0x0000000000122000) (database page 289 (0x121)) for 4096 (0x00001000) bytes failed verification due to a page checksum mismatch. The expected checksum was 69681549426688 (0x00003f6000004000) and the actual checksum was 1244332967133 (0x00000121b80644dd). The read operation will fail with error -1018 (0xfffffc06). If this condition persists then please restore the database from a previous backup. This problem is likely due to faulty hardware. Please contact your hardware vendor for further assistance diagnosing the problem.

Catalog Database (1436) Catalog Database: The database page read from the file "C:\Windows\system32\CatRoot2\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\catdb" at offset 1536000 (0x0000000000177000) (database page 374 (0x176)) for 4096 (0x00001000) bytes failed verification because it contains no page data. The read operation will fail with error -1019 (0xfffffc05). If this condition persists then please restore the database from a previous backup. This problem is likely due to faulty hardware. Please contact your hardware vendor for further assistance diagnosing the problem.

Occasionally, this warning also appear:
Windows (620) Windows: A request to write to the file "C:\ProgramData\Microsoft\Search\Data\Applications\Windows\Windows.edb" at offset 8159232 (0x00000000007c8000) for 8192 (0x00002000) bytes succeeded, but took an abnormally long time (60 seconds) to be serviced by the OS. This problem is likely due to faulty hardware. Please contact your hardware vendor for further assistance diagnosing the problem.

I previously thought that HDD needs to be checked for error and defragmented. I did those, but problems persisted. I checked the web amd I found this (http)://gunnalag.wordpress.com/2011/04/21/repair-and-verify-system-catalog-database-integrity/ {I must use the brackets otherwise I cannot post this}
I followed the steps, but then I found Jet file not found - Error 1811

I use CCleaner to repair registry, but I often get missing MUI Reference from CCleaner. The latest one is oobefldr -33057.

Did I by accident removed important file? Is the virus still inside my HDD and cause this recurring issue? I have downloaded the latest virus definition from Microsoft, but still no luck on detecting anything. If I by accident deleted a file, is it possible to get a file replacement from the internet? I'm totally lost here.

I'd greatly appreciate any helps and pointers.