I have a fast computer (quad-core i7, 3.5 Ghz, 24 GB of RAM, Windows 8.1) and I installed a new hard drive less than a year ago that was supposed to be as fast as you could buy for an HHD and not an SSD.
On boot, the computer is extremely slow for about 20 minutes (literally 20 minutes). Nothing will load. Opening programs will just hang.
Went into Resource Monitor and found that my disk I/O is at 100% that entire period. In fact, it looks like one program is just going to town on my disk:
CompatTelRunner.exe. I've Googled it, but there are hardly any results, so I don't know what service this is.
It could be a hard drive issue (Windows 8.1 Update 1 Disk Usage 100%), but HD Tune shows burst rate at 22.8 MB/s and average around 81.0 MB/s