Hmm... this is an interesting thread because I have been having a similar, although not identical problem with the Issues scan on my computer ever since version 1.34 of CCleaner. My problem is that CCleaner runs through the Issues scan, but once it gets to 100% (i.e., the scan has finished) it takes 20-30 seconds for the "Fix selected issues..." button to become active. My CPU usage does not spike and my mem usage stays relatively low. I've found that choosing to cancel the scan after it reaches 100% lets me fix the listed issues right away (instead of having to wait the half a minute or so), so this problem was never too serious for me, since I had a workaround. It is simply a minor nuisance. But since others are having troubles with CCleaner's Issue scan, I figured I'd throw this out there.
Software Specs:
CCleaner 1.35.424
Windows XP Professional Edition (all patches up to date)
ZoneAlarm Free 6.5.737.000 (firewall)
Avast! 4.7.892 (antivirus)
Hardware Specs:
AMD Athlon 64 X2 4200+ (CPU)
ASUS A8R32 MVP Deluxe (mobo)
BIOS version 0602 (newest non-beta BIOS for this board)
ATI Radeon x1900XT w/ 512 MB GDDR3
3,072 MBs Corsair DDR running in single channel
320 GB Seagate HD (SATA II, OS drive)
320 GB and 500 GB Seagate HDs (SATA II, additional drives)
Oh, and if it would help, I could list my running processes as well. I have a number of programs running all the time (such as Shareaza, Rainlender, Picasa2, etc.), which I suppose could be potentially interferring with CCleaner. I don't recall making any major software changes at the time of me noticing the problem, so I'm inclined to believe it is a bug in CCleaner itself, as opposed to interference from another app. But I'm not certain. Like I said, not a huge problem for me, so maybe just give it a glance whenever you get a spare minute or two. Thanks again for the great FREE program MrG!