My friend's computer is super slow for some reason. He has a decent Dell laptop, but lately, it's been really slow. In fact, it's so slow that when you click on the screen, the loading cursor pops up and wont go away unless you move it to the taskbar (but it still doesn't click). We tried CCleaner and Malwarebytes, and those improved the boot time, but not the loading cursor problem. It works in Safe Mode, but you can't uninstall stuff or play games. Does he need to delete everything except Windows off of his laptop? If so, how?
There are multiple reasons why laptop may be slow:
1) bad sector on hard drive will slow a laptop down most common problem
2) you still have some spyware in the system some spyware have rootkits malwarebytes misses some of the new ones download kaspersky rescue cd burn to iso and boot from cd and scan.
3) Corrupt system files and UN-registered dll files can also cause slow downs do a chkdsk
4) fan is blocked by dust and cpu is throttling and overheating.
To fix 1 and 3 go to my computer right lick on C: drive and select properties-> tools-> error checking click check now button and check off both boxes it will ask to check on next restart select yes and restart.
after if it still does the same thing go to http://www.bleepingcomputer.com/
Download combofix and run it in safe mode after it shows log restart computer.
Download Junkware Removal Tool and AdwCleaner run adwcleaner first then junkware removal tool.
#4 is really tricky and should only be done by a computer tech you could try canned air and try to blow out dust BUT if dust plug is large enough it could make thing worse and seize up the fan.
Most times the dust plug builds up on the heat sink fin blocking air flow and laptop has to be taken apart and cleaned should only be done by a computer tech.