I have updated to "boinc_7.4.36_windows_x86_64_vbox.exe" on my Windows 7 x64 and it would no longer launch. I have been running BOINC successfully for years and now I'm totally locked out. The client window cannot connect to localhost.

Here's what I found in the "stderrdae.txt" file that contains some error info:

Unhandled Exception Detected...

- Unhandled Exception Record -
Reason: Access Violation (0xc0000005) at address 0x000000013F43F331 read attempt to address 0x00001000

Engaging BOINC Windows Runtime Debugger...

BOINC Windows Runtime Debugger Version 7.4.36

Dump Timestamp    : 03/13/15 21:01:05
Loaded Library    : dbghelp.dll
LoadLibraryA( symsrv.dll ): GetLastError = 126
LoadLibraryA( symsrv.dll ): GetLastError = 126
LoadLibraryA( srcsrv.dll ): GetLastError = 126
LoadLibraryA( srcsrv.dll ): GetLastError = 126
Loaded Library    : version.dll
Debugger Engine   : 4.0.5.0
Symbol Search Path: C:\ProgramData\BOINC;C:\Program Files\BOINC;srv*C:\ProgramData\BOINC\symbols*http://msdl.microsoft.com/download/symbols;srv*C:\ProgramData\BOINC\symbols*http://boinc.berkeley.edu/symstore

lots of info about loaded modules

*** Dump of the Process Statistics: ***

- I/O Operations Counters -
Read: 335, Write: 325, Other 344

- I/O Transfers Counters -
Read: 1286561, Write: 467315, Other 14210

- Paged Pool Usage -
QuotaPagedPoolUsage: 138608, QuotaPeakPagedPoolUsage: 138608
QuotaNonPagedPoolUsage: 13192, QuotaPeakNonPagedPoolUsage: 13192

- Virtual Memory Usage -
VirtualSize: 7831552, PeakVirtualSize: 84738048

- Pagefile Usage -
PagefileUsage: 7831552, PeakPagefileUsage: 7831552

- Working Set Size -
WorkingSetSize: 13017088, PeakWorkingSetSize: 13017088, PageFaultCount: 3210

*** Dump of thread ID 5712 (state: Initialized): ***

- Information -
Status: Base Priority: Normal, Priority: Normal, , Kernel Time: 0.000000, User Time: 0.000000, Wait Time: 0.000000

- Unhandled Exception Record -
Reason: Access Violation (0xc0000005) at address 0x000000013FEEF331 read attempt to address 0x00001000

- Registers -
rax=00000000e40b5f99 rbx=0000000000000000 rcx=000000000022f930 rdx=0000000000000000 rsi=0000000000000000 rdi=000000003ff481e0
r8=0000000000000100 r9=00000000755523c0 r10=00000000004c1300 r11=000000000022f908 r12=0000000000000100 r13=0000000000000000
r14=0000000000000001 r15=0000000000000000 rip=000000003feef331 rsp=000000000022f770 rbp=000000000022f930
cs=0033  ss=002b  ds=002b  es=002b  fs=0053  gs=002b  efl=00010206

- Callstack -
ChildEBP RetAddr  Args to Child
0022f900 3feafced 03241470 03241470 3ff482d8 00397c70 boinc!+0x0 
0022fa40 3fe77a5c 00000000 00000000 3ff481e0 66666600 boinc!+0x0 
0022fc30 3feb4e12 00567a68 00567a68 00567a94 00000003 boinc!+0x0 
0022fc70 3feb5390 00567a68 00000000 00000000 10010011 boinc!+0x0 
0022fd70 3fee99ea 00000001 00000000 00000000 00000000 boinc!+0x0 
0022fda0 779c59ed 00000000 00000000 00000000 00000000 boinc!+0x0 
0022fdd0 77bfc541 00000000 00000000 00000000 00000000 kernel32!BaseThreadInitThunk+0x0 
0022fe20 00000000 00000000 00000000 00000000 00000000 ntdll!RtlUserThreadStart+0x0 

*** Dump of thread ID 30432781 (state: Initialized): ***

- Information -
Status: Base Priority: Normal, Priority: Unknown, , Kernel Time: 34359738368.000000, User Time: 21474836480.000000, Wait Time: 0.000000

- Registers -
rax=0000000000000000 rbx=0000000000000000 rcx=0000000000000000 rdx=0000000000000000 rsi=0000000000000000 rdi=0000000000000000
r8=0000000000000000 r9=0000000000000000 r10=0000000000000000 r11=0000000000000000 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=0000000000000000 rip=0000000000000000 rsp=0000000000000000 rbp=0000000000000000
cs=0000  ss=0000  ds=0000  es=0000  fs=0000  gs=0000             efl=00000000

- Callstack -
ChildEBP RetAddr  Args to Child
(-nosymbols- PC == 0)
00000000 00000000 00000000 00000000 00000000 00000000 !+0x0 

*** Debug Message Dump ****

*** Foreground Window Data ***
    Window Name      : 
    Window Class     : 
    Window Process ID: 0
    Window Thread ID : 0

Exiting...

I tried uninstalling and reinstalling to no avail.