Vista - Backup and Chkdsk Issues

So I am trying to partition my hard drive to dual boot Vista and Windows 7, hoping the latter will prove to be a faster and overall better operating system. I use my computer heavily daily and can therefore not afford much (if any) downtime, so I essentially must do everything right on the first try. In preparation for my partitioning (since I don't want to delete any of the data I already have), I am trying to back up my computer using the Windows Backup tools. I created a 170 GB partition on my external HD for backup, and Windows seems to let me proceed through the backup until it flashes that C: has corruption and Chkdsk must be run. This is where my issues begin.

I had issues getting Chkdsk to start, but resolved them with a new System32 file (autochk.exe?) found in these forums. So finally chkdsk started when I booted my computer and seemingly froze at 17% (later to find, it was just running extremely slowly), so I did a hard shut down, holding the power button. I retried, determined it was running slowly through the processes or something along the line (step 4/5) and let it proceed all night. I woke up this morning and was relieved it was on step 5/5, but my roommate told me it had been at 10,010 files out of very many for at least three hours.

Why does this keep freezing??? I have tried many times and continually get the same problem. And I certainly don't want to skip the backup because I most likely will not partition correctly the first time.

Thank you.

P.S. Here are my computer specs, if it matters:

Dell XPS 1530
2.6 Ghz Core 2 Duo
4 GB RAM
320 GB Samsung HM320JI
GeForce 8600 M GT 256 MB vRAM

Welcome to the forum. Few sectors of the HDD might have gone bad. is there anyway you can run hardware test? you may find hardware test in BIOS.

Prasath