Charging thinkpad tablet - howto acquire 5vdc 2A supply

[mark]

My tablet needs 5v, 2A to charge via the micro usb but all I have is a
700ma walwart (which does not work) so I was thinking I could use my ATX
power supply. There are 2 rails on the ATX for 5v, one for 30a and one for
2a. Is there any reason I cannot use either rail? The tablet will only
draw the current it needs, right?

 

[mike]

My tablet needs 5v, 2A to charge via the micro usb but all I have is a
700ma walwart (which does not work) so I was thinking I could use my ATX
power supply. There are 2 rails on the ATX for 5v, one for 30a and one for
2a. Is there any reason I cannot use either rail? The tablet will only
draw the current it needs, right?

Don't do it!!!
There are several reasons that this is risky.
And none of them have anything to do with the numbers printed
on the labels.
Yes, you'll find 100 people who say it's ok.
And maybe 10 who say they've done it successfully.
But not likely any who used your exact supply on your exact tablet.
99% probability that it will work fine is of little
solace if you're the 1%.
If you knew what you were doing, you wouldn't be here asking.
Bottom line:
Get a supply designed for this kind of application.