Reccent loss of wifi signal strength

Hello,

Having a weird wifi problem. I have a Dell Studio 1555 laptop that's about a year old. Wireless internet connection has never been a problem. (The adapter is a Dell Wireless 1397 WLAN Mini-Card. OS is Windows 7)

All of a sudden yesterday it started struggling to pick up a wifi connection. It's like it's gone very faint and I can only really pick up connection when I'm a metre or two away from the router.

I know it's not a problem with my home router as I've had the same problem today in an office and a Starbucks, which are usually fine.

Any ideas what I can do??

Thanks.

I've been on device manager and made sure the driver is up to date. (it's