Sounds like maybe hardware, however if you are running the minimum amount of RAM (1gb) then that could be a issue depending on what all is going on in the background on your system. Could be a hard drive going bad also, really could be any part of your hardware. As it started happening after OS change, make sure that you have all your drivers installed and that they are all working properly. Just click the windows button (bottom left corner), then click CONTROL PANEL, then DEVICE MANAGER (Switch to small thumbnail view for easier operation) it will be on the 2nd or 3rd line down. Also when you installed your new OS did you UPGRADE, or did you do a CLEAN INSTALL? At this point if you UPGRADED I would just start all over and do a CLEAN INSTALL, fallow the instructions in windows 7 installation choosing the FORMAT drive 0 (your local disk) then complete the installation. After it restarts the couple of times and your actually on your account on windows 7. Choose the automatic updates, let these finish (reboot/shutdown as prompted) Then go to www/hp.com/downloads and find the drivers for you laptop (open device manger instructions above) and download all the drivers that have flags in your device manager. Then do Windows Update again, DON'T download Internet Explorer 9 at this time (ignore it for a few days/weeks) Also you can try this before all the above, as sort of test of your hard drive/file system. Power up let it boot, open up COMPUTER, right click choose PROPERTIES, then TOOLS, then click the check now button. When this opens check the other box (both box's need to have a check mark in then) It will tell you that it can't preform this as the device is in use, and ask if you would like to preform this test the next time your computer REBOOTS (choose YES and REBOOT) This process could take anywhere from 10 minutes to several hours if your HDD is damaged. Good luck hope this helps, let me know if you need more tips or come up with more info to pass back at me, so I can offer more assistance.