Help cannot access anything!

Can anybody give any advice on a problem I have just started to get on my ipone 3G? Since yesterday I cannot access any apps, emails or even text's as soon as I try to access anything it just takes me back to my main front screen! I have spent ages trying to find an answer on the net and nothing!

Has anybody any suggestions withouth having to wipe out the whole thing? I am not very savvy with technology so any advise greatly apppreciated.

Thanks