USB Flash drive not working

I have a newish 16Gb Cruzer flash drive with U3 disabled, which upon insertion into PC (using winXPsp3), is detected and opens selection menu, upon which i select "Open to view files", it states access denied.
Then when I enter My computer and click on Removable Disk, another dialogue box "Open With" starts, asking me with which program to open it!!??
An older 1GB drive does similar, but after access denied, its U£ kicks in, and i can explore thru that!
HELP!

 

Thanks, never said I wanted to remove U3, but anyway upon inserting I did a scan and it found an autorun trojan, now sorted and working!

 

I am again having an issue with same flash drive, in that I can now not see it in My Computer to access (or scan for viruses etc.), although it makes sounds on insertion, and repeats another immediately as it self ejects.
I have tried on 2 XP PCs.
Please help..