Sindura,

1. Kuch karne se pehle aap apna sim card kisi doosre mobile mein daal kar dekhiye. Phir try sending an sms. Agar sms nahi jaata, us doosre mobile ki message center number check kariye. Chances are, it will work!

2. Virus, SIM card mein nahi ja sakta. SIM card ke liye viruses nahi hote hain kyunki normal phone se re-programming a simcard to embed a virus in the SIMs memory is impossible. Virus ho sakte hain toh phones ke. Aapka virus aapke phone pe ho sakta hai ya uske Memory card pe ho sakta hai. Iske liye, aap in mein se koi antivirus install kariye:

F-Secure:
http://www.download.com/F-Secure-Anti-Virus-for-S60-Third-Edition/3000-1...

Kaspersky:
http://handheld.softpedia.com/get/Security/Antivirus/Kaspersky-Anti-Viru...

Commander Mobile:
http://www.download.com/Commander-Mobile-Anti-Virus/3000-11138_4-1041417...

McAfee:
http://www.mobango.com/media_details/mcafee_virusscan_mobile_v1_11_os7/T...

Kuch karne se pehle apne contacts wagerah backup kar lijiye. Aur jab tak antivirus se scan nahi kiya tab ka apna memory card kisi doosre phone mein nahi daaliye. Aapki problem mostly phone badalne se solve ho jaani chahiye.

Hope this helps. Good luck!