'download from their site' - whose site? MS Downloads do not expire.
Please fill in your system specs so that we can see what sort of machine we're talking about.
I take it that the three-disk install is from HP - is one described as being th eoperating system disk, and the others Applications and drivers
, or do you have to use all three?
Did the HP's bundled software include an Anti-virus? - that should be uninstalled, and the AV manufacturer's removal/cleanup utility should be run to remove interferences to any replacement you install.
Note that many current AV's will cause problems with Vista RTM - including a non-genuine response from WGA - and it's worth downloading the standalone installers for both SP1 and SP2 on another machine, and installing them while offline.
The fact that the Restore disks took 6 hours is worrying - it almost certainly means that either
1) you still have malware/virus problems
2) your disk is failing.
You can check the disk by using the HD manufacturer's test utility - it will probably also have a 'low level format' option which , assuming the drive passes testing, you should consider using, as it will return the drive to a totally clear state.