Bumped up to 3rd level support, but got lots of info
I was having the same trouble and I even got bumped up to 3rd level support.
The list below covers what we did, but in the end I enabled Windows Defender and changing the power options to HIGH PERFORMANCE. I would try that first and possibly save a lot of work.
Third party antivirus programs don't seem to play well with Windows 8. I tried several, even a paid one (VIPRE drove me crazy). Some antivirus programs need special uninstall programs from the vendors website, even though you'll see one in the install folder. Always check.
We ended up doing the following (I think I have it all listed)
Increased pagefile to equal RAM size (can even double it, but I didn't need to)
Ran Disk Cleanup
Disabled the Windows Search Indexing service and re-enabled it later
Checked for updates and checked for failed updates
Ran Microsoft Security Scannerwith the included antivirus scan.
Microsoft Safety Scanner - Free Virus Scan with the Microsoft Safety Scanner
Boot in Safe Mode. Run current antivirus programs
Clean Boot with only Microsoft services.
Check Device manager to see if drivers needed updating (may need to look for a Windows specific version, the Manufacturer website may install bloatware)
Re-start Windows in SAFE MODE WITH NETWORKING mode.
Check that disk performance to see if the new driver helped.
I then
enabled about half the Startup items, and re-started Windows 8 normally.
Go through each of the Startup Items and disabled them one by one then re-started in normal mode. (May find "bloatware" from manufacturer.
If still too high:
Disable all items in Task Manager Statup, then re-start Windows in SAFE MODE WITH NETWORKING mode.
Start Windows as trouble shooting and run repair the Windows Image
Run sfc /scannow from CMD prompt as administrator.
Start Windows normally and look to see what process are the most active.
Open Task Manager and click on Details tab.
Right click the columns headers and click "Select Columns".
From the "Select Columns" window, check: I/O Reads, I/O Writes, I/O read bytes, I/O write bytes and then click OK.
Now the columns will be added to the view and will display how much each process is utilizing from the hard disk.
Sort by I/O read bytes or I/O write bytes by clicking on the column header to see which process is utilizing the HD mo
If you want to re-enable the Startup programs, only enable a few at a time.
To check for disk error within the Windows:
Improve performance by optimizing your hard drive - Windows Help
Finally, try changing the power options to HIGH PERFORMANCE
