Usually, you can not borrow unless you are currently employed. You may need to roll it into your current employer's plan in order to borrow.
Sorry, but i have to agree with Mr. Defrance on this one. You will have to be currently employed with the company in order to take out a loan on your 401k balance.
I agree with both of the answers above. I would just add that if you are currently unemployed or your new employer does not offer a 401k and you have an emergency need for cash please don't cash out your entire balance as that will trigger a 10% early withdrawal penalty if under 59 1/2 + taxes at your highest bracket.
Do a tax free rollover to an IRA account and from there take only the portion that you need, a 401k will not allow a partial distribution (on most cases). Your distribution from the IRA will be subject to the 10% penalty and taxes but the rest of the balance can hopefully stay in the account and fulfill its mission to help you in retirement.
Best of luck!
How old are you?