Hi, Could you send more information about these issues (like screen shot of BSOD, is it randomly on VM but fix on host or random on Host and VM, …)
Mean while, may be these KB from “VMware Site” become useful, “KB1019253“, “KB1027921” and “KB1005208 (problem on booting)“

Dear Maziyar,

First of all, which licensing do you use on you host?
I’m asking this question because “the free version of VMware ESXi does not support SNMP” (refer to “VMware ESX and ESXi 4.0 Comparison“)**.

For configuring the SNMP on your ESXi servers you can use “vicfg-snmp.pl” command which you can find in “VMware vSphere CLI” or “VMware vSphere Management Assistant”.

1. Use following command to configure your host
HOSTNAME would be the name or IP address of VMware ESX/ESXi server
USERNAME would be the account on the host like “root”
PASSWORD would be the password for the specified username like password for “root” account
SNMP_RECEIVER would be the name or the IP address of monitoring server
PORT would be the port number on the monitoring server which is opened for receiving data
SNMP_COMMUNITY_STRING would be the snmp key would be use with server and client both

Command:
vicfg-snmp.pl –server HOSTNAME_IP –username USERNAME –password PASSWORD -t SNMP_RECEIVER@PORT/SNMP_COMMUNITY_STRING

Example:
vicfg-snmp.pl –server 192.168.10.31 –usename root –password ****** -t 192.168.10.14@162/mysnmpkey
or
vicfg-snmp.pl –server esxi50-1.kasraeian.com –username root –password ****** -t mon.kasraeian.com@162/mysnmpkey

2. Use the following command for checking the configuration on the server:
Command:
vicfg-snmp.pl –server –username –password –show

Example:
vicfg-snmp.pl –server 192.168.10.31 –username root –password ****** –show
or
vicfg-snmp.pl –server esxi50-1.kasraeian.com –username root –password ****** –show

3. If the configuration is ok, enable the SNMP on the host by following command:
Command:
vicfg-snmp.pl –server –username –password –enable

Example:
vicfg-snmp.pl –server 192.168.10.31 –username root –password ****** –enable
or
vicfg-snmp.pl –server esxi50-1.kasraeian.com –username root –password ****** –enable

4. For testing purpose following command can be used:
Command:
vicfg-snmp.pl –server –username –password –test

Example:
vicfg-snmp.pl –server 192.168.10.31 –username root –password ****** –test
or
vicfg-snmp.pl –server esxi50-1.kasraeian.com –username root –password ****** –test

Also you can refer to the “KB1008065” for more details.

** Note:
If you are using VMware Hypervisor (the free edition), you can find your free license on the download page, so you would use hypervisor even after your trial period with some limitation of course; so if you entered you license key as soon as you installed your “VMware ESXi”, you can change your licensing to the trial again so you would be able to configuring your host for SNMP and then re-entering your license for “Hypervisor”.

Hope you find it useful
Feel free to contact me if you need any other information or help