2 DOA USB Jump drives?

[MPTech]

I was having problems with one of my PCs a month or so ago. Turned out to be a bad Power Supply, but it was working sporadically for several weeks. During that time, I plugged-in one of my jump drives to copy some data. It was taking a tremendous amount of time to copy and I was getting error messages, then nothing. So I thought it must be a Jumpdrive problem and grabbed another one I had. The second one started having similar issues, so I quit. After I replaced the PSU, the PC has performed very well, but now the Jumpdrives are both non-functioning.
I've tried them in 3 other PCs and every PC recognizes them when I plug them in (I hear the ding, and they appear in My Computer), but I cannot open them and when I look at their properties, both display "0 bytes". I also tried to re-format them, it tells me "There is no disk in the drive E. Insert a disk, and try again".
Both of these jumpdrives are 4GB and worked great until my failing PC somehow corrupted them. (they are different brands too, Centon DataStick Pro and Toshiba)

Are they toast?

[SuperSparks]

If the bad PSU sent a significant overvoltage to the drives they certainly could be Try reformatting the drives from Disk Management, it sometimes seems to go better from there.