I have a problem with two USB sticks.
Here is the story:
Two days ago I bought a new PC with eight-core processor and a good graphic card. Before that I had two computers, a very old one and not so old one. On these two computers I was able to open all my USB sticks, whether they were 2, 4, 8 or 16 GB. My newest computer (with XP SP3) was able to open all of them except one. I didn't bother with that. I installed windows 8 pro on that PC and then I tried to plug in one of my 8 GB sticks. The little lamp on it turned on, but the computer didn't see it and it wasn't visible neither in My Computer nor in Disk Management. I tried to do it with my other 8 GB stick, but the same story, only the lamp didn't even turn on. The only stick he seems to recognize so far is a 16 GB USB stick. Later I tried to plug those two 8 GB sticks in another computer, but now they didn't function there either.
BTW I have tried to plug in those two sticks in all possible USB ports on my new PC, both 2.0 and 3.0. And I checked the drivers. They are all up to date.
I need help, please. I have valuable files on those USB sticks.
If there are issues with the USB ports, the hardware could have been fried on the thumb drives. See if a PC repair shop can move the memory chips into another USB drive. And get the PC repaired, should be under warranty if it's new.
Did everything work fine before you installed Windows 8 on it? Did you check if the PC even has Windows 8 support? Where did you get a "new" computer that has XP on it even?