If Bobby Fischer was mental stable and alive today, would he be posting in forums here today?

I kinda doubt it.

is anyone mentally stable that plays chess?

Oh he'd be obsessively getting into flame wars with everyone, especially when some nut would ask for a good move 4 in the Nimzo and then start arguing with him.

he might have had issues but not so bad to warrant a sentence on the chesscom forums.

pretty much be cmibu

I am a newbie here, what is cmibu?

checkmateibeatu, one of the dullest trolls from around 4-5 years ago.

In his last years in Iceland, 2005...2007, did he make any use of internet?

It's said, despite of his claims of not being interested in classical chess anymore, once he was watching a game in TV (yes, they show chess games in TV in Iceland) and made a phone call to the program to spot a combo nobody had noticed.

For interest, the list of eldest grandmasters yet alive. I counted 43 who are older than Fischer:

1. Averbakh 1922/1952
2. Taimanov 1926/1952
3. Benko 1928/1958
4. Bisguier 1929/1957
5. Matanovic V 1930/1955
6. Krogius VII 1930/1964
7. Korchnoi 23 III 1931/1956
8. Lein 28 III 1931/1964
9. Pomar Salamanca IX 1931/1962
10. Nikolac IV 1932/1979
11. Kraidman XI 1932/1976
12. Vasiukov III 1933/1961
13. Padevsky V 1933/1964
14. Penrose X 1933/1993
15. Ivkov XI 1933/1955
16. Darga 1934/1964
17. Fridrik 26 I 1935/1958
18. Nikolic 26 I 1935/1977
19. Panno 17 III 1935/1955
20. Uhlmann 29 III 1935/1959
21. Matulovic VI 1935/1965
22. Forintos VII 1935/1974
23. Barcsay II 1936/1967
24. Malich XI 1936/1975
25. Spassky I 1937/1955
26. Portisch IV 1937/1961
27. Bukic 2 XII 1937/1976
28. Lombardy 4 XII 1937/1960
29. Marovic I 1938/1975
30. Spiridonov II 1938/1979
31. Zaitsev V 1938/1976
32. Radulov 7 I 1939/1972
33. Hecht 29 I 1939/1973
34. Csom VI 1940/1973
35. Todorcevic XI 1940/1989
36. Petkevich XII 1940/2002
37. Gaprindashvili V 1941/1978
38. Murey VIII 1941/1987
39. Parma XII 1941/1963
40. Kovacevic III 1942/1976
41. Rajkovic VI 1942/1977
42. Vukic VIII 1942/1975
43. Jansa XI 1942/1974

So... between these 43 masters, which of them are currently, as of 2016, posting in forums?

They aren't nuts, are they?

Him and the inibomber would be tearing it up.