B is the ramdrive created by the boot cd to run, it is (as per the name) entirely in the ram, and will be removed when the system restarts.
C *may* be the recovery image location, I'm not entirely sure, this is my best guess
D is your normal C drive, and has your windows installation and everything.
you don't have to do anything, this is all normal behaviour for your system and the boot CD.
I hope you like windows 7, I like it a lot more than windows xp.
Elitebook 8440p, i5 520, 8gb, Samsung 840 SSD
Old/Not Working/Dead Laptops:
T61 7661CC2, 4gb, Windows 7 x64, 240gb intel SSD, 500gb Ultrabay drive
Toshiba Portege 7020ct
Thinkpad T41 23737FU
Dell Latitude LS