Sudden drop in SERP

help me to figure this out.

[jcmiras]

Dear webmasters,
Please help me to figure out why my website suddenly drop from google search last weekend until now. PLease help me to figure out what ive done wrong by confirming the following theories;

1. I have several number of websites and these are all inter-link. Does Google penalize me for that?

2. To increase the interlinking inside my website, i use a (.) (dot) as an anchor text that link to the other pages of my website. Does Google penalize me for that?

3. I use javascript and forms for outbound links.
Does Google penalize me for that?

4. I participated in Link Exhange. Most of these websites that link to me have content that are not relevant to the content of my website. BUT, i dont link back to them. Does Google penalize me for that?

5. I have several pages which have the same content. Does Google penalize me for that?

Thats all and may you help me with my problem.
Thanks.

[Adversity Sure Fire]

These all resons are enough to get penalize. :(

I am shocked that in most of the google forums, senior memeber have been posting about quality content, relevant linking and no web rings. Still you used all these. Now what to say.