Hello,

I have a particular SD card that, whenever I try to insert it into my computer's SD slot, not only slows down the computer drastically, but also makes the following message POP up: " F:\ is not accessible. The request could not be performed because of an I/O device error."

This only occurs with that particular SD card. My other SD card works fine. The SD card that doesn't work is a brand-new PNY Optima SD HC. My computer is a HP Pavilion a818n.

Any suggestions?  The root of the problem may be this:
SD cards are up to 2GB only. To read and write above that capacity, the standards were updated, SDHC was born, & CERTAIN h/w revisions have to be in place, such that older equipment (that includes, but is not limited to digital cameras, video camcorders, & card readers) that specifically only catered for SD WILL NOT read or write to SDHC cards. NO firmware or s/w patch can undo or repair this one little inconvenience because the changes are in the h/w (electronics), MEANING they are physical and can't be undone or revised by ANY s/w you can introduce. A similar case would be that of legacy USB and USB2.0. Of course newer equipment will necessarily read and write to both SD and SDHC.
Plugging an SDHC card to SD only-equipment might even damage one or both.
to coody, this means therefore that you should stop forcing your camera to deal with SDHC cards because it wasn't designed for that. Use only SD cards with it (which means 2GB maximum). Memory cards are not formatted in the same sense as hard disk drives are; even so, there are little programs in the WWW that you can use to force cards to have, for example, a FAT32 file system. But even if you do this to an SDHC card with an appropriate card reader on your PC (certainly not the reader you have now which is SD-only), your SD card-only camera will still not recognize it.
SDHC cards are now available up to sizes of 32GB, and they NEED equipment duly marked "SDHC" to use them.

To give credit where it is due this is being quoted from an article appearing at this site;
http://www.videohelp.com/forum/archive/compatible-problem-sd-vs-sdhc-card-t360520.html
truenorth